Foundry molding machines have been utilized to make both cores and molds. In one prior art type of foundry molding machine, the core or mold is made in the cavity of two mold boxes and then the core or mold, hereinafter called a mold, is held in one of the mold boxes which swings so that the cavity faces downwardly. An ejection plate with ejection pins is then actuated downwardly to eject the mold downwardly out of the cavity onto some transfer device.
In another type of prior art foundry molding machine the mold produced in the mold cavity of the two mold boxes is retained in the upwardly facing cavity as the mold boxes are separated. Subsequently an ejector plate and ejector pins are moved upwardly to move the mold up out of the cavity to a position sufficiently elevated so that a fork may be moved in transversely with the tines of the fork between the ejector pins. Then the pins are lowered to transfer the mold onto the fork and the fork then retracts laterally.
In both of these types of machine the mold is caused to be moved by the ejection means and this movement relative to the cavity in which it had previously been located often causes breakage of the mold. The machines of the first type, namely the downward ejection of the core or mold out of the downwardly facing cavity, was generally restricted in use to rather robust molds which could drop onto their receiving conveyor without breaking. It was also used primarily for smaller mold items. In one prior art production machine of the second type mentioned above, namely the upward ejection of the mold, a particularly delicate mold was being produced which was long and thin with many areas of thin cross-sectional area. A production rate of 70 to 75 percent, with a scrap rate of 25 to 30 percent in production of the molds, was about the best that could be produced hence was considered acceptable.
The problem to be solved accordingly is how to manufacture in high production quantities fragile or delicate mold without having a large scrap rate.